Clamp device for electrical extension cords



Sept. 8, 1959 E. 1. GILMAN ET AL 2,903,669

CLAMP DEVICE FOR ELECTRICAL EXTENSION CORDS Filed April 24, 1956 22, 20 Mun/Z, Lz'ddy, A/El/Wrlson 5 March United States Patent CLAMP DEVICE FOR ELECTRICAL EXTENS ION CORDS This invention relates to clamping devices adapted to be used with electrical extension cords and the like, to hold together plug and socket or similar fittings.

Where electrical power is temporarily required at a place remote from an outlet, recourse is generally had to the use of electrical extension cords, and if the place is an appreciable distance away it is often necessary to employ several extension cords, connected one to the other. Such uses of extension cords are commonly resorted to, for example, when it is desired to employ an electric drill, an electric sprayer, electric lawn mower, electric lights or any of innumerable pieces of equipment which are currently available on the market. During the employment of such equipment it often occurs that a pull is inadvertently given the extension cord, whereupon it will become disconnected at the juncture of the plug and socket. This is inconvenient and wasteful of time, since it requires that the user walk a distance, which may be as much as 50 feet, to re-establish the connection and then again walk back to the place at which the equipment is being used.

The present invention overcomes this disadvantage in the use of electrical extension cords as above pointed out, and an object of the invention is to provide an extremely simple and inexpensive clamping means for holding together a coupled plug and socket or other similar electrical juncture means.

Another object of the invention is to provide an improved clamping means of the above type, which is characterized by a quick-acting mechanism enabling the clamping members to be simply pushed toward each other and automatically locked when embracing the electrical plug and socket or other electrical fittings.

Yet another object of the invention is to provide an improved clamping device of the above character, which is adaptable for use with each and every variety of plug and socket or equivalent connector means currently available on the market.

A still further object of the invention is to provide an improved electrical-fitting clamping device as above set forth, having incorporated in it a simple, push-button arrangement to enable the device to be readily unlocked for separation of the clamping means when it is desired to disconnect the coupled ends of the extension cord.

A feature of the invention resides in the provision of an improved clamping device in accordance with the above, which may be readily manufactured from simple, cast and machined parts, which has relatively few components, and which is sturdy and reliable in its operation at all times, and resistant to severe and rough usage.

Other features and advantages will hereinafter appear.

In the drawings accompanying this specification, similar characters of reference indicate corresponding parts wherever possible in the several views, in which:

Fig. 1 is a perspective view of the improved clamping device of this invention, attached to a mating plug and socket to hold the same locked together.

Fig. 2 is a side elevational view of the clamping device.

Fig. 3 is an exploded view, in vertical section, of the two clamping members of the device.

Fig. 4 is a transverse sectional view taken on line 4-4 of Fig. 3.

Fig. 5 is a transverse sectional view taken on line 5--5 of Fig. 3.

Fig. 6 is an elevational view of the push button member of the clamping device.

Fig. 7 is an elevational view of the locking spring of the device.

Referring to the drawings, the improved clamping device of the present invention comprises a pair of oppositely-disposed jaws 10 and 11 which have preferably a shallow dish-like shape, said jaws being provided with radial cuts 12 and 13 respectively, extending from their upper edges to their central portions. The cuts 12 and 13 are adapted to receive the cables 14 and 15 of electrical extension cords, and the clamping jaws or shells 10 and 11 are so shaped and arranged as to engage electrical fittings such as the socket fitting 16 and plug fitting 17 shown in Fig. 1.

For the purpose of manipulating and locking the clamping jaws or shells 10 and 11 we provide a slide bar 18 having a plurality of ratchet teeth 19 along its upper edge. The bar 18 is rigidly secured in a hub 20 of the shell 10, said hub being preferably cast as an integral part of the shell, as shown, and having a circular bore to receive a reduced-end portion 21 of the bar 18. The hub 20 and bar 18 may be secured together in any suitable manner, as for example by the use of a press-fitted pin 22.

The bar 18 is of square or rectangular cross section, and slidably carries a hub 23 cast as an integral part of the shell 11, said hub having a square opening closely slidably fitting the bar.

In accordance with this construction the jaws or shells 10 and 11 may be made to approach each other or to separate from each other, merely by sliding the jaw 11 along the bar 18, as will be readily understood.

For the purpose of automatically locking the jaw 11 in any adjusted position we provide a locking annulus 25 having a square opening 26 through which the bar 18 extends. The annulus 25 functions in the manner of a push button, and is carried in a slot 26 in the hub 23, being normally urged downward by a spring 27 disposed in a recess 28 in the hub, as shown.

It will be understood that the locking annulus 25 may have a knife edge as indicated at 28 in Fig. 6, thereby to enable it to coact with the ratchet teeth 19. The knife edge 28 functions in the manner of a cam, and in conjunction with the spring 27 will enable the jaw 11 to be readily slid from right to left along the bar 18, but will automatically lock the jaw against retrograde movement from left to right.

Accordingly, by the provision of our novel shell-like clamping jaws 10 and 11 with radial slots 12 and 13, said jaws being connected by the ratchet bar 18, it is possible to easily and quickly apply the clamp to the connected ends of two extension cords or the like and to quickly clamp together the coupled socket and plug thereof. We have found that, by the use of such a clamp, there is obviated the annoyance due to separation of coupled sockets and plugs as occasioned by inadvertent pulls on the extension cords. Release of the clamping device may be easily effected by upward pressure on the push button member 25, which releases the jaw 11 and enables it to he slid along the bar 18 from left to right.

Variations and modifications may be made within the scope of the claim and portions of the improvements may be used without others.

We claim:

A clamping device for locking together the coupled ends of extension cords having mating contact fittings, comprising a pair of jaw means having oppositely-disposed walls adapted to engage the oppositely-disposed ends of said electrical fittings when the latter are coupled together; a slide ='bar secured to one of said jaw means; and a bearing structure carried by the other jaw means, providing a bearing through which the slide bar extends, said bearing structure fitting closely about said bar and holding the latter against arcuate movement in any direction while enabling the bar to move longitudinally therein, thereby to enable said jaw means to be brought toward each other with purely translational movement for embracing the said fittings and preventing separation thereof; cooperable, releasable locking means on the slide bar and other jaw means, automatically locking said jaw means in their adjusted clamping positions, said coop- References Cited in the file of this patent UNITED STATES PATENTS 540,555 Mader June 4, 1895 1,638,848 Hargrave Aug. 16, 1927 2,406,567 Schueneman Aug. 27, 1946 2,473,321 Yanko June 14, 1949 2,638,574 Webb May 12, 1953 2,720,633 Westberg Oct. 11, 1955 

